They will be charged the same as those parking at the Ulster Hospital.

The cost of parking at the Ulster Hospital site currently ranges from £1.20 for up to one hour and £4.50 for between eight and 24 hours.

In a statement the trust said it recommended a "phased approach" to the extension of car parking charges across the Ards, Lagan Valley and Downe/Downshire Hospital sites.

"This will reflect current and projected demand, parking capacity and availability of capital funding to provide the necessary infrastructure," it said.

"Staff parking rates will be standard across all sites."

Income from parking charges will initially be used to offset the cost of operating the system which would require cameras, barriers, ticket payment machines and additional staffing, with surplus cash spent on patient services.

There are exemptions for some patients including those undergoing renal dialysis and cardiac rehabilitation, as well as for relatives who are driving the patient.

"At a time of austerity where cuts are hitting so many I think it is particularly callous the trust will introduce the charges at this time. But I'm not surprised," he said.

"Staff at Lagan Valley who have been forced to endure four years of pay freezes will now have to pay their own employer to do a day's work."

Fearghal McKinney MLA, a member of the Stormont health committee, said families could face "repeated costs" with the implementation of these charges.

He said: "If there are people visiting they are going to be subjected to repeated costs. It is money-raising and they advertise that this goes to offset expensive care, but my worry is that it will land on the people who may not be able to afford to pay.

"I find it to be a creeping tax on people. It is the most vulnerable who are there for a long time and who are charged disproportionately."

The trust said exemptions will be allowed to ensure that people most in need "do not experience financial hardship".